"Man Claims Mystery Drone Drained His Drone's Full Battery in 3-Minutes"
I don't know the details, but if weather was freezing then no surprise presumed lithium battery died. But doesn't explain why presumed lithium battery in mystery drone didn't die.
I don’t know, but several witnesses said these drones are loud like motorcycles, so they must have ICE engines or small jet engines.............
Perhaps the "mystery drones" are using electric generators powered by small gasoline engines.
These craft are not hand-launched items you can purchase from Amazon. They are the size of automobiles, and larger. There are many alternatives for the propulsion systems.